The present invention relates to hypodermic syringes and, more particularly, to a safety hypodermic syringe, which enables the needle assembly to be received inside the plunger in the barrel after the service of the safety hypodermic syringe.
Hypodermic syringes must be collected and properly disposed of after their service to prevent possible contamination and transmission of diseases, for example, AIDS, hepatitis, etc. However, because the needle cannula is disposed outside the barrel after the service of the hypodermic syringe, the medical person who settles the waste hypodermic syringe tends to be injured by the needle cannula when handling the waste hypodermic syringe. In order to prevent direction contact of the hands with the needle cannula of a waste hypodermic syringe, a protective cap may be used and covered on the needle assembly. However, this method is not perfect because the protective cap tends to be forced out of the needle assembly by an external force. There is known a safety hypodermic syringe, which enables the needle assembly to be pulled backwards with the plunger and received inside the barrel after the service of the safety hypodermic syringe. However, because the plunger is separated from the needle assembly and removed from the barrel and cannot be inserted into the barrel again after the needle assembly has been received inside the barrel, much storage space is required for the used safety hypodermic syringe. There is known another structure of safety hypodermic syringe in which the plunger has a front hook, which hooks on a part of the needle assembly after the service of the safety hypodermic syringe, for enabling the needle assembly to be pulled backwards with the plunger and received inside the barrel in a tilted position. However, because the plunger has a part extended out of the rear side of the barrel after the needle assembly has been received inside the barrel in a tilted position, the plunger and the needle assembly tends to be pulled out of the barrel accidentally.
The present invention has been accomplished to provide a safety hypodermic syringe, which eliminates the aforesaid drawbacks. It is one object of the present invention to provide a safety hypodermic syringe, which enables the needle assembly to be received inside the plunger within the barrel after the service of the safety hypodermic syringe. It is another object of the present invention to provide a safety hypodermic syringe, which has parts received one within another to minimize storage space after the service. The safety hypodermic syringe of the invention comprises a barrel, a needle assembly mounted in a front neck of the barrel, a tubular plunger with a rubber stopper inserted into the barrel, and a pull handle inserted into the plunger and adapted to pull the needle assembly backwards to the inside of the plunger in the barrel after the service of the safety hypodermic syringe. The pull handle has a middle neck through which the rear part of the pull handle can easily be separated from the front part of the pull handle by bending, enabling the separated rear part of the pull handle to be inserted into the plunger in the barrel and hooked up with the front part of the pull handle.